Intercommunicating telephone system



H. C. EGERTON INTERCOMMUNICATING TELEPHONE SYSTEM Filec} May 27 1920 k /hven for: fienry C/gge/ fon.

Patented Mar. 33, 1924.

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mTEB/COMLMUNICATING TELEPHONE SYSTlTiL- Application filed May 27, 1920. Serial 310. 884,531

To all whom it may concern.

A Be it known that I, HENRY G. EonR'roN, a citizen of the United States, residing at Maplewood, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Intercommunicating Telephone Systems, of which the following is a full, clear, concise, and

. exact description.

This invention relates in general to telephone systems and especially to intercommunicatmg systems.

The invention is applicable to paging or announcing systems about hotels, warehouses, factories or the like, where it is of advantage to use an alternative system for loud speaking or private communication.

The object of the invention is to provide an intercommunicating telephone system which may be used forthe purpose of announcing from'any station .or for private conversation between stations.

In accordance with this invention in its preferred form, a plurality of similar stations are bridged to a number of common feeder lines or wires and provided with switching means to connect a common battery source. Each station is provided with a telephone transmitter, a head receiverand' receiver. Additional.

a loud speaking switching means 13 located at each of the stations, which, when 0 erated at any two or more stations, cuts 0 the loud speaking receivers of all stations and permits persons at suchsta ions where the switches are operated to carr y on a private conversation between stations.

The invention may be more completely understood by referring to the drawing which shows it in its preferred form. The system comprises a plurality of similar stations, of which station A and station B only are shown.

Five common conductors are rovided as follows: a common lead 1, a tal ing lead 2, a batter feed lead 3, a battery supply wire 4, a tal ing lead 5.

A common battery su' ply 6, is bridged across leads 1 and 4 for t e purpose of supplying stations.

I Station A comprises a transmitter 7, an induction coil 8 associated therewith, a loud speaking receiver 9, a mechanical-amplifier key 22, operatin energizing current to the. various.

22. A. transmitter 7 with its associated in duction coil 8 is bridged to the leads 1 and 3, and the energizing winding of the mechanical amplifier 10 is likewise bridged to the leads 1 and 3. Similarly at station B, the transmitter 15 and the induction coil 16' are bridged to leads 1 and 3, and the energizing winding of the mechanical amplifier 18 is also bridged to the leads 1 and 3. The switch keys 13 and 21 are provided with two contacts 23 and 24, which contact when the keys are operated to connect the battery supply lead 4 with the battery feed lead 3. Thus, when key 13; or key 21, or keys corresponding thereto and at the other stations are operated, battery current is supplied to the transmitters and mechanical amplifiers of all the stations in the system. Keys 13 and 21 are provided with contacts, 25, 26, 27, 28, 29 and 30 whose functions will later become evident from the description of the operation of this circuit. Keys 14 and 22 are provided with contacts 31, 32, 33, 34 and 35, whose function will also be described hereinafter.

When a party at station A desires to communicate with a party at any other station, he operates key 13 which closes the contacts 23' and 24 to sup ly current to the entire system, as before escribed. Voice currents produced in the transmitter 7 are reproduced in ,the secondary winding of the induction coil 8 and take the following path: secondary of induction coil 8, contacts 28 and 29 of the key 13, contacts 33 and 31 of the key 14, lead 2, contacts 31 and 33 of the winding of mechanical amplifier 18, lea 1 to secondar winding of induction coil 8. The alternations in the operating winding of amplifier 18 cause osclllations in the armature and the current flowing from the lead 1 through the carbon button of amplifier 18, primary winding of the induction coil 19 to lead 3, contacts 23 and 24 of the key 15 to the lead t and battery supply 6, reproduces these voice currents in the secondary winding of the induction coil 19 and the loud speaking receiver 1?.

ln answering back at the transmitter 15, the voice currents reproduced in the secondary of the induction coil. 16 take the following path: secondary winding of the'in duction coil 16, contacts 28 and 27 of key 21, lead 5, receiver 12, contacts 26 and 25 of key 13, lead 1, through the secondary winding of the induction coil 16. The lorealring of contacts 29 and 30 of key 13 opens'the short circuit anound a resistance 38, placing resistance 38 in serieswith the operating winding of the mechanical amplifier 10 by cutting down the volume of tone through this amplifier.

Should it he desired to hold a rivate conversation between any two stations, A. and B, of thesystem, keysj 13, 14., 21 and 22 are operated. The head receivers are then used at both stations. The speech currents from transmitter of station A follow the following path: secondary winding of the induction coil 8', contacts 28 and 29 of key 13, contacts 33 and 34 of key 14, lead 5, receiver 20, contacts 26 and 25 of key 21, lead 1, through the secondary of induction coil 8. The resistance elements 36 and 37 are shunted across the leads 1 and 5 by the operation of the keys 1 and 22 respectively, in order to cut own excessive transmission when only the two stations A and B are carrying on a private conversation.

Contacts 32 and 31 operate to connect the leads 1 and 2"therehy short-circuiting the mechanical amplifiers and preventing their operation.

What is claimed is:

l. ln a telephone system having a plurality of stations, switching means provided at each station to simultaneously connect said station in intercommunicative relation with every other station, and additional switching means at each such station to exclude from intercommunicative relation all of such stations where the said additional switching means is not operated.

2. In a telephone system, a plurality of stations, a plurality of common conductors therefor, a source of current, switching means provided at each station to connect said station in intercommunicative relation with every other station, and additional switching means at each such station to ex elude all of such stations where the said additional switching means is not operated.

3. ln a telephone system, a pluralit of stations, each station comprising a telep lone transmitter, a loud speaking receiver, and a head receiver; a common source of current; a plurality of conductors common to all stations; and. switching means provided at each incense station to simultaneously connect said station in inter-communicative relation with all the other stations.

d. In a telephone system, a plurality of stations, each station comprising a telephone transmitter, a loud speaking receiver and a head receiver; a common source of current; a plurality of conductors common to all stations; switching means provided at each station to simultaneously connect said station in intercommunicative relation with all other stations; and additional switching means to exclude all of such stations where said additional switching means is not operated.

5. In a telephone system, a plurality of stations, each station comprising a telephone transmitter, a loud speaking receiver and a head receiver; a common source of current; a plurality of conductors connecting said stations; switching means provided at each station cooperating with the said conductors to connect simultaneously any one station in intercommunicative relation with all other stations.

6. In atelephone system, a plurality of stat-ions, each comprising a telephone transmitter, a loud speaking receiver and a head receiver; a common source of current; a plurality of conductors connecting said stations; switching means provided at each station cooperating with the said conductors to connect simultaneously any one station in intercommunicative relation with all other stations; and additional switching means to exclude all of such stations where the additional switching means is not operated.

7. ln a telephone system, a plurality of stations, each comprising a telephone transmitter, loud speaking receiver means and a head receiver; a common source of currenta pair of conductors therefor common to all such stations; -a conductor common to all stations and adapted, when connected with such battery source, to supply such current to each of the said stations; switching means at each station to establish such connection; transmission conductors common to all such stations; and other switching means at each station to connect simultaneously any one station in intercommunicative relation with all other stations.

8. In a telephone system, a plurality of stations, each comprising a telephone transmitter, loud speaking receiver means and a head receiver; a common source of current, a pair of conductors therefor and common to all such stations; a conductor common to all said stations and adapted, when connected with such battery source, to supply such current to each of the said stations;

' switching means at each station to establish such connection; transmission means common to all said stations including a con ease ductor; an additional conductor associated with the head receiver of each station; other switching means at each station to connect the transmitter of any one station in talking relation with the loud speaking means of the other stations and to connect the transmitters'of the said other stations in talking relation with the head receiver of the said one station; and additional switching means to connect the head receivers and the transmitters of all stations in talking condition Where all said switching means are operated.

9. In a telephone system, a plurality of stations each having a loud speaking receiver, a head; receiver and a transmitter, and means at each station for connecting the loud speaking receivers at all other stations in communicative relation with the transmitter of the station Where such means is operated, and; to associate the head receiver of such station in communicative rela tion with the transmitters of all the other stations.

In itness whereof, I hereunto subscribe my name this 22nd; day of May, A. D; 1920- HENRY C. EGER-TON. 

